SLIDING GATE APPARATUS

In order to reliably avoid releasing of surface pressure application during opening/closing control of a nozzle hole while realizing opening/closing control of the nozzle hole in a state of surface pressure application between a fixed plate and a slide plate, and control of switching between application and release of surface pressure in the same slide device, this sliding gate apparatus comprises: a fixed plate fixed to a molten-steel container; a slide plate for opening and closing a nozzle hole, the slide plate being moved in sliding fashion relative to the fixed plate; a slide device for moving a case for retaining the slide plate; and a surface pressure control mechanism for switching between a state of surface pressure application and a state of surface pressure non-application between the fixed plate and the slide plate. The surface pressure control mechanism has a support bar member supported so as to be able to move relative to the fixed plate, a connection block fixture for switching between a connected state in which the support bar member and the case are interlocked by mounting to each other and a disconnected state in which the support bar member and the case are non-interlocked by unmounting from each other, and a spring member for generating a force for applying surface pressure in accordance with the position of the support bar member.